In the past, several soil diggers have been made which included complicated mechanisms that are expensive to manufacture and prone to sticking and malfunctioning. U.S. Pat. No. 6,338,512 shows a vertical motion for closing the diggers together through the use of a toggle mechanism device that pulls the two scoops together when the vertical motion is performed. This device, whose use is taught in the '512 patent, is inserted (pushed) into the soil with a vertical motion that limits the force that can be applied to the digger. In some cases, where the soil is heavy, this vertical motion could cause user fatigue very quickly. Also, the complicated toggle mechanism takes considerable force to close and can be prone to sticking.
Larger diggers, such as post hole diggers, have been in use for many years. This type of digger is two handled in use, and was designed to make large holes in the soil, mostly to accommodate wooden fence posts.
Post hole diggers are operated by holding the long handles closely together to maintain the diggers in the open position. The post hole digger is then driven into the soil in a vertical motion. When the digger comes to a stop, the handles (one in each hand), are pulled away from each other, closing the two diggers, entrapping the soil between the scoops. Pulling the digger out of the soil will remove the trapped soil and leave a hole in the earth. Often, repeated cycles of this digger are required to get to the correct depth of the desired hole.